The mobility of devices has become highly desirable. Moreover, many devices now interact with wireless systems and, consequently, many devices are blurring the line between wireless networks and traditional computer systems. For instance, some personal digital assistants can connect to wireless networks, such as a cellular phone network, while many cellular telephones now connect to the Internet through wireless networks.
A benefit of mobile devices is that the devices can be used to connect to local information services, such as information services providing local traffic, weather, or telephone numbers, when traveling. It is possible for a person using a cellular phone to determine the phone number of a local pizza parlor, for instance, or learn what the traffic is like on a major thoroughfare.
While the mobility of devices is desirable, it can also create problems. For instance, information services that provide traffic reports are only valid for particular areas Therefore, a person whose cellular phone is set to connect to a local Internet site providing local traffic information will not be of use when the person is at a remote location. Similarly, information services that provide directory services such as telephone numbers and addresses usually have only a certain geographical area for which the provided information is relevant. Outside this geographical area, the information is generally irrelevant.
Thus, what is needed are techniques for allowing mobile devices to access services when the mobile devices travel between areas.